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Β-carotene

β-Carotene
Skeletal formula
Space-filling model
Names
IUPAC name
beta,beta-Carotene
Systematic IUPAC name
1,3,3-Trimethyl-2-[3,7,12,16-tetramethyl-18-(2,6,6-trimethylcyclohex-1-en-1-yl)octadeca-1,3,5,7,9,11,13,15,17-nonaen-1-yl]cyclohex-1-ene
Other names
Betacarotene, β-Carotene, Food Orange 5, Provitamin A, 1,1'-(3,7,12,16-Tetramethyl-1,3,5,7,9,11,13,15,17-octadecanonaene-1,18-diyl)bis[2,6,6-trimethylcyclohexene]
Identifiers
3D model (Jmol)
ChEBI
ChemSpider
ECHA InfoCard 100.027.851
EC Number 230-636-6
E number E160a(i) (colours)
PubChem CID
UNII
Properties
C40H56
Molar mass 536.89 g·mol−1
Appearance Dark orange crystals
Density 0.941 g/cm3
Melting point 176–184 °C (349–363 °F; 449–457 K)
decomposes
Boiling point 654.7 °C (1,210.5 °F; 927.9 K)
at 760 mmHg
Insoluble
Solubility Soluble in CS2, benzene, CHCl3, ethanol
Insoluble in glycerin
Solubility in dichloromethane 4.51 g/kg (20 °C)
Solubility in hexane 0.1 g/L
log P 14.764
Vapor pressure 2.71·10−16 mmHg
1.565
Pharmacology
A11CA02 (WHO) D02BB01 (WHO)
Hazards
Harmful Xn
R-phrases R20/21/22, R36/37/38, R44
S-phrases S7, S15, S18, S26, S36
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 0: Exposure under fire conditions would offer no hazard beyond that of ordinary combustible material. E.g., sodium chloride Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point 103 °C (217 °F; 376 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YesYN ?)
Infobox references

β-Carotene is an organic, strongly colored red-orange pigment abundant in plants and fruits. It is a member of the carotenes, which are terpenoids (isoprenoids), synthesized biochemically from eight isoprene units and thus having 40 carbons. Among the carotenes, β-carotene is distinguished by having beta-rings at both ends of the molecule. β-Carotene is biosynthesized from geranylgeranyl pyrophosphate.

β-Carotene is the most common form of carotene in plants. When used as a food coloring, it has the E number E160a. The structure was deduced by Karrer et al. in 1930. In nature, β-carotene is a precursor (inactive form) to vitamin A via the action of beta-carotene 15,15'-monooxygenase.

Isolation of β-carotene from fruits abundant in carotenoids is commonly done using column chromatography. It can also be extracted from the beta-carotene rich algae, Dunaliella salina. The separation of β-carotene from the mixture of other carotenoids is based on the polarity of a compound. β-Carotene is a non-polar compound, so it is separated with a non-polar solvent such as hexane. Being highly conjugated, it is deeply colored, and as a hydrocarbon lacking functional groups, it is very lipophilic.

Plant carotenoids are the primary dietary source of provitamin A worldwide, with β-carotene as the most well-known provitamin A carotenoid. Others include α-carotene and β-cryptoxanthin. Carotenoid absorption is restricted to the duodenum of the small intestine and dependent on class B scavenger receptor (SR-B1) membrane protein, which are also responsible for the absorption of vitamin E (α-tocopherol). One molecule of β-carotene can be cleaved by the intestinal enzyme β,β-carotene 15,15'-monooxygenase into two molecules of vitamin A.


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Wikipedia

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